Generally, a bicycle is energy-free and environment-friendly. Unlike other transportation means, bicycles are convenient for a short-distance travel because they are driven by rider's pedaling. However, they require more physical strength than walking or running when travelling an uphill. In that case, bicycling may be harmful to user's health.
In recent years, electric bicycles, hybrid bicycles, and the like are being developed. They are equipped with electric batteries (70) and electric motors (41) so that a rider can more easily travel an uphill which requires hard pedaling.
An electric bicycle can travel has a basic function of a typical bicycle, i.e., traveling by rider's pedaling power. In addition thereto, it also can travel without pedaling using an easy and automatic driving function. An electric battery (70) and an electric motor (41) are installed in the electric bicycle for the automatic driving.
A passive-driving bicycle (passive driving by foot motion and pedal) can be used for a short distance travel, a workout for health, or a hobby for well-being life.
An automatic-driving bicycle, which is operated by rotation of the electric motor (41) using the electric battery (70), is more proper for a person, such as elderly people, who is in need of care for a long distance travel. The automatic-driving bicycle requires less physical power consumption and thus proper for a tough driving on a slope or for a lone distance travel.
In recent years, the electric bicycles have been in an increasing demand due to its convenient automatic drive and due to growth of an aging population either at national level or at international level. Still, more research and efforts are underway to develop superior technology, performance, and convenience.
A conventional electric bicycle adopts a pedal assist system (PAS) or a throttle system. In the pedal assist system (PAS), an electric power is automatically provided by the electric motor (41) to assist a pedaling power based on a pedaling and a load. In the throttle system, a rider activates a throttle to have the electric motor (41) operated in the similar manner as in a scooter or a motorcycle.
The throttle method is advantageous in that it is possible to automatically travel at a constant speed. However, it is considerably inconvenient that a user has to manually control operations during driving. See Korean Patent Registration Nos. 10-1530171 and 10-1527487.
The pedal assist system is convenient for manipulation and operation in that an electric power is automatically provided by the electric motor (41) to assist a pedaling power based on a pedaling and a load. However, its critical disadvantage is a constant speed automatic driving is not available. In addition, a control range is also very limited. In this aspect, there are limitations in improving functionality and convenience of an electric bicycle.